Front-end architectures for wireless applications

ABSTRACT

Front-end architectures for wireless applications. A front-end system can include a first assembly of filters having a first transmit filter and configured to provide a duplexing functionality in which a first transmit signal is filtered by the first transmit filter when in a first frequency-division duplexing mode, and a second assembly of filters having a second transmit filter and configured to provide a duplexing functionality in which a second transmit signal is filtered by the second transmit filter when in a second frequency-division duplexing mode. The front-end system can further include a receive path having the first transmit filter such that a received signal is filtered by the first transmit filter and routed to a receive output node when in the second frequency-division duplexing mode. The front-end system can further include a switching circuit configured to facilitate the routing of the received signal to the receive output node.

CROSS-REFERENCE TO RELATED APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57. Thisapplication is a continuation of U.S. application Ser. No. 14/263,852filed Apr. 28, 2014, entitled DUPLEXER ARCHITECTURES AND METHODS FORENABLING ADDITIONAL SIGNAL PATH, which claims priority to and thebenefit of the filing date of U.S. Provisional Application No.61/817,288 filed Apr. 29, 2013, entitled CIRCUITS AND METHODS RELATED TODUPLEXER ARCHITECTURE FOR ENABLING ADDITIONAL SIGNAL PATH, the benefitsof the filing dates of which are hereby claimed and the disclosures ofwhich are hereby expressly incorporated by reference herein in theirrespective entirety.

BACKGROUND Field

The present disclosure generally relates to duplexer architectures inwireless applications.

Description of the Related Art

Wireless communication systems such as cellular systems, operatingfrequencies are typically assigned to different bands. A given wirelessnetwork can utilize a number of such frequency bands to facilitatetransmission (TX) and/or receive (RX) operations.

Many wireless devices are configured to provide duplex capability toallow TX and RX operations to be performed generally concurrently. Intime-division duplexing (TDD) systems, duplexing can be achieved by useof synchronized sequence of TX and RX operations in a given frequency.In frequency-division duplexing (FDD) systems, duplexing can be achievedby use of different frequencies for the TX and RX operations.

SUMMARY

In some implementations, the present disclosure relates to a frequencydivision duplexing (FDD) system that includes a transmit (Tx) pathconfigured for passage of a Tx signal in a first frequency band duringoperation in a first mode. The FDD system further includes a receive(Rx) path configured for passage of an Rx signal in a second frequencyband during operation in a second mode. The second mode is differentthan the first mode, and the second frequency band has at least someoverlap with the first frequency band. The FDD system further includes abandpass filter implemented along the Tx path and along the Rx path. Thebandpass filter is configured to filter the Tx signal when in the firstmode and to filter the Rx signal when in the second mode.

In some embodiments, the first band can include at least a portion of aB28 Tx band. The first band can be a B28A Tx band having a frequencyrange of 703 MHz to 733 MHz. The second band can be a B29 Rx band havinga frequency range of 716 MHz to 728 MHz.

In some embodiments, the bandpass filter can be a part of a duplexerconfigured for duplex operation in the first mode. In some embodiments,the second mode can be an Rx-only mode.

In some embodiments, the FDD system can further include a post-poweramplifier (post-PA) switch configured to receive and route the Tx signalfrom a PA to the bandpass filter. The post-PA switch can be furtherconfigured to receive and route the Rx signal from the bandpass filterto a receiver. The post-PA switch can include a double-pole-2-throw(DP2T) switch functionality to facilitate operation in the first mode,the second mode, and a third mode. The first mode can include a B28Aduplex mode, the second mode can include a B29 Rx-only mode, and thethird mode can include a B28B duplex mode.

In some embodiments, the FDD system can further include an antennaswitch configured to receive and route the Tx signal from the bandpassfilter to an antenna. The antenna switch can be further configured toreceive and route the Rx signal from the antenna to the bandpass filter.The antenna switch can be configured to include a single-pole-M-throw(SPMT) functionality, with the quantity M being an integer greaterthan 1. The single pole can be in communication with the antenna, andone of the M throws can be in communication with the bandpass filter.The sharing of the bandpass filter between the Tx path and the Rx pathcan result in the quantity M being less than N by at least 1, with thequantity N being integer greater than M and representative of a numberof throws in a configuration where the Tx path and the Rx path do notshare a bandpass filter.

In some embodiments, the sharing of the bandpass filter between the Txpath and the Rx path can result in a number of filters associated withthe first frequency band and the second frequency band being reduced byat least one.

In some embodiments, the FDD system can be configured to operate in onlyone of the first and second modes at any given time. In someembodiments, the first mode can be configured for operation in a firstgeographic region and the second mode can be configured for operation ina second geographic region. The first and second geographic regions canbe sufficiently separated to inhibit operation in one mode in anon-corresponding geographic region.

In accordance with a number of implementations, the present disclosurerelates to a method for operating a wireless device having a frequencydivision duplexing (FDD) system. The method includes detecting awireless network. The method further includes determining whether anetwork change is desired. The method further includes performing aswitching operation, if the network change is desired, to change betweena transmit (Tx) signal path of one network and a receive (Rx) signalpath of another network, where both of the Tx signal path and the Rxsignal path share a common filter.

According to some implementations, the present disclosure relates to aradio-frequency (RF) module that includes a packaging substrateconfigured to receive a plurality of components. The RF module furtherincludes a frequency division duplexing (FDD) system implemented on thepackaging substrate. The FDD system includes a transmit (Tx) pathconfigured for passage of a Tx signal in a first frequency band duringoperation in a first mode. The FDD system further includes a receive(Rx) path configured for passage of an Rx signal in a second frequencyband during operation in a second mode. The second mode is differentthan the first mode, and the second frequency band has at least someoverlap with the first frequency band. The FDD system further includes abandpass filter implemented along the Tx path and along the Rx path. Thebandpass filter is configured to filter the Tx signal when in the firstmode and to filter the Rx signal when in the second mode. In someembodiments, the RF module can be a front-end module (FEM).

In a number of teachings, the present disclosure relates to a wirelessdevice that includes a transceiver configured to process radio-frequency(RF) signals. The wireless device further includes a frequency divisionduplexing (FDD) system in communication with the transceiver. The FDDsystem is configured to facilitate routing of the RF signals. The FDDsystem includes a transmit (Tx) path configured for passage of a Txsignal in a first frequency band during operation in a first mode. TheFDD system further includes a receive (Rx) path configured for passageof an Rx signal in a second frequency band during operation in a secondmode. The second mode is different than the first mode, and the secondfrequency band has at least some overlap with the first frequency band.The FDD system further includes a bandpass filter implemented along theTx path and along the Rx path. The bandpass filter is configured tofilter the Tx signal when in the first mode and to filter the Rx signalwhen in the second mode. The wireless device further includes an antennain communication with the FDD system. The antenna is configured totransmit the Tx signal and receive the Rx signal.

In some embodiments, the wireless device can be configured to be capableof operating in the first mode at a first geographic location and in thesecond mode at a second geographic location. The first and secondgeographic locations can be sufficiently separated to inhibit operationin one mode in a non-corresponding geographic region.

In some implementations, the present disclosure relates to a duplexingarchitecture having a bandpass filter implemented for operation in aB28A Tx band and a B29 Rx band. The present disclosure also relates to afront-end module having a signal routing circuit that includes abandpass filter implemented for operation in a B28A Tx band and a B29 Rxband. The present disclosure also relates to a wireless device having aduplexing architecture that includes a bandpass filter implemented foroperation in a B28A Tx band and a B29 Rx band. One or more features ofthe present disclosure can also be implemented in other combinations ofcellular frequency bands.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the inventions have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment of the invention.Thus, the invention may be embodied or carried out in a manner thatachieves or optimizes one advantage or group of advantages as taughtherein without necessarily achieving other advantages as may be taughtor suggested herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts a wireless device having a duplexer architecture capableof operating in a first mode when in a first wireless network, andoperating in a second mode when in a second wireless network.

FIG. 1B shows an example where a first network and a second network canboth be accessible by a wireless device at a given location.

FIG. 2 shows an example architecture configured to allow a wirelessdevice to operate in example bands B28 and B29 that are typicallyimplemented in geographically separated regions.

FIG. 3 shows an architecture similar to the example of FIG. 2, but witha dedicated B29 Rx filter removed to reduce cost and size associatedwith the architecture.

FIG. 4A shows an example switching configuration that can be utilized tofacilitate the example architecture of FIG. 3.

FIG. 4B shows a switching circuit that can be implemented as an exampleof the switching configuration of FIG. 4A.

FIG. 5 shows a process that can be implemented to achieve one or morefeatures as described herein.

FIG. 6 shows another process that can be implemented to achieve one ormore features as described herein.

FIGS. 7 and 8 show processes that can be implemented as more specificexamples of the processes of FIGS. 5 and 6.

FIG. 9 depicts a wireless device having one or more advantageousfeatures described herein.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The headings provided herein, if any, are for convenience only and donot necessarily affect the scope or meaning of the claimed invention.

Disclosed herein are circuits and methods related to duplexarchitectures for enabling one or more additional radio-frequency (RF)signal paths utilizing one or more existing components. In someembodiments, such a feature can be implemented in wireless devices thatare configured to operate in different networks. By way of an example,FIG. 1A depicts a wireless device 102 having a duplexer architecture 100operating in a first mode in a first wireless network 104. In a secondwireless network 106, the duplexer architecture 100 of the same wirelessdevice 102 can be configured to operate in a second mode.

In the example of FIG. 1A, the first and second networks 104, 106 can beseparated geographically with sufficient distance so that the wirelessdevice 102 can only operate in one of the two example modes at any giventime. For example, there are operating cellular frequency bands that canoverlap, but are assigned for usage in separated locations such as NorthAmerica and Asia.

Various examples are described herein in the foregoing context of twogeographically-separated wireless networks. However, it will beunderstood that one or more features of the present disclosure can alsobe implemented in a situation where two networks are not necessarilyseparated geographically as in the example of FIG. 1A. FIG. 1B shows anexample where a first network (114, Network A) and a second network(116, Network B) can both be accessible by a wireless device 102 at agiven location. A duplexer architecture 100 can be configured so thatthe wireless device 102 can operate in either network (Mode A or Mode B)by performing an appropriate mode-switching operation.

FIG. 2 shows an example architecture 130 configured to allow a wirelessdevice to operate in example bands B28 and B29 that are typicallyimplemented in geographically separated regions. In FIG. 2, a portion ofthe architecture 130 corresponding to the B28 band is generally depictedas 132, and a portion of the architecture 130 corresponding to the B29band is generally depicted as 134.

B28 band is a long term evolution (LTE) frequency division duplexing(FDD) band (Tx=703-748 MHz, Rx=758-803 MHz) which is typically used inAsia. In some applications, the B28 band is implemented as B28A(Tx=703-733 MHz, Rx=758-788 MHz) and B28B (Tx=718-748 MHz, Rx=773-803MHz). Each of the B28A and B28B bands is typically provided with its ownduplexer, due to, for example, challenges associated with bandwidth andduplex gap. Further, in some regions such as Japan, there can be anissue associated with coexistence with digital TV.

Band 29 is an LTE band recently defined and released by the 3rdGeneration Partnership Project (3GPP) organization, for use in theUnited States for an Rx-only band (716-728 MHz). Such a band can becarrier aggregated with high bands where both Tx and Rx active FDD linkcan then add this B29 Rx-only band for an increase in downlink datarate.

In the example architecture 130 of FIG. 2, the B28 band can beconfigured as follows. For transmission, an RF signal can be provided(through path 140) to a power amplifier (PA) 142. Such a PA can be aband-specific PA, or a PA capable of amplifying RF signals in the B28band. For the purpose of description, the PA 142 can also be referred toas a B28 Tx PA.

An output of the B28 Tx PA 142 can be provided to a post-PA switch 146through path 144. The post-PA switch 146 can be, for example, asingle-pole-two-throw (SP2T) switch configured to receive the amplifiedTx signal and route it to either a B28A duplexer 150 (also referred toas B28A DPX) through path 148, or a B28B duplexer 162 (also referred toas B28B DPX) through path 160.

When operating in the B28A mode, the amplified Tx signal can be filteredby a Tx filter 152 (e.g., a bandpass filter) of the B28A duplexer 150,and the filtered output can be routed to an antenna switch 190 (e.g., anantenna switch module (ASM)) through path 156. In such an operatingmode, a pole 192 of the antenna switch 190 can be connected to the throwassociated with the path 156 so as to route the amplified and filteredTx signal to an antenna 196 through path 194.

In duplex operation, a signal can be received through the antenna 196and be routed to an Rx filter 154 (e.g., a bandpass filter) of the B28Aduplexer 150 through the path 194, the switch 190, and the path 156. Afiltered output of the Rx filter 154 can be processed as an Rx signalthrough path 158.

Similarly, when operating in the B28B mode, the amplified Tx signal canbe filtered by a Tx filter 164 (e.g., a bandpass filter) of the B28Bduplexer 162, and the filtered output can be routed to the antennaswitch 190 through path 168. In such an operating mode, the pole 192 ofthe antenna switch 190 can be connected to the throw associated with thepath 168 so as to route the amplified and filtered Tx signal to theantenna 196 through path 194.

In duplex operation, a signal can be received through the antenna 196and be routed to an Rx filter 166 (e.g., a bandpass filter) of the B28Bduplexer 162 through the path 194, the switch 190, and the path 168. Afiltered output of the Rx filter 166 can be processed as an Rx signalthrough path 170.

When operating in the B29 (Rx) mode, a signal can be received throughthe antenna 196 and be routed to the antenna switch 190. The pole 192 ofthe switch 190 can be connected to the throw 188 so as to route thereceived signal to an Rx filter 182 (also referred to as B29 Rx) throughpath 180. A filtered output of the Rx filter 182 can be processed as anRx signal through path 184.

In the example architecture 130 of FIG. 2, the antenna switch 190 can bea single-pole-N-throw (SPNT), with the pole 192 in communication withthe antenna 196, and one of the throws (e.g., throw 188) being dedicatedto the B29 Rx filter 182. It is noted that the channel associated withthe throw 188 and/or the B29 Rx filter 182 can increase the cost andsize requirement in the architecture 130.

As described herein, the example bands B28 and B29 are typicallyimplemented in geographically separated regions. Accordingly, a givenwireless device will likely not be subjected to these two bands at thesame time.

It is noted that the B29 Rx band (716-728 MHz) overlaps with the B28A Txband (703-733 MHz). Thus, in some implementations, the B28A Tx filter(152 in FIG. 2) can be used for a B29 Rx path. As described herein byway of an example, such a configuration can allow removal of the channel(e.g., throw 188 in FIG. 2) and the dedicated B29 Rx filter 182, therebyreducing cost and size associated with the duplexer architecture 100.

FIG. 3 shows a configuration 200 that can be an example of such aduplexer architecture 100. In the example of FIG. 3, Tx signal input140, PA 142, and PA output 144 can be similar to those described inreference to FIG. 2. Also, duplex operations of the B28A and B28B bandscan also be generally similar to those described in reference to FIG. 2.

As shown in FIG. 3, a B28A Tx filter 152 of a B28A duplexer 150 canprovide dual functionality. First, the B28A Tx filter 152 can providefiltering of an amplified Tx signal from the PA 142. The amplified Txsignal from the PA 142 can be provided to the B28A Tx filter 152 througha switch 202. The filtered Tx signal can be routed to an antenna 196through path 210, a SP(N−1)T antenna switch 220, and path 194 so as tobe transmitted as a B28A Tx band signal. Second, the B28A Tx filter 152can provide filtering of a signal received by the antenna 196 and routedin reverse through the same path (the path 194, the antenna switch 220,and the path 210) so as to yield a filtered Rx signal. The filtered Rxsignal is shown to be routed through the switch 202 and path 206 forfurther processing as a B29 Rx band signal.

In some embodiments, the foregoing routings (the amplified Tx signalfrom the PA 142 to the B28A Tx filter 152, and the filtered Rx signalfrom the B28A Tx filter 152 to the B29 Rx path 206) as well as therouting of an amplified Tx signal from the PA 142 to the B28B Tx filter164 can be achieved by the switch 202. An assembly 208 of the switch 202with its input and output paths is shown in greater detail in FIG. 4.

As shown in FIGS. 3 and 4, the switch 202 can be a double-pole-2-throw(DP2T) switch. In FIG. 4A, node A corresponds to the B29 Rx path 206,node B corresponds to the path 204 into the B28A Tx filter 152, node Ccorresponds to the path 160 into the B28B Tx filter 164, and node Dcorresponds to the path 144 from the PA 142. Within the switch, the path144 (node D) can be connected to a first pole 230, and the path 204(node B) can be connected to a second pole 236. The path 160 (node C)can be connected to a first throw 232, and the path 206 (node A) can beconnected to a second throw 234. Each of the first and second poles 230,236 can be switched between the first and second throws 232, 234 tothereby provide the DP2T switching functionality.

FIG. 4B shows an example switching circuit 240 that can provide the DP2Tfunctionality of the switching configuration 208 of FIG. 4A. In FIG. 4B,the nodes A-D and their corresponding paths (206, 204, 160, 144) andpoles/throws (234, 236, 232, 230) are similar to those described inreference to FIG. 4A.

FIG. 4B further shows that the switching circuit 240 can include a firstswitch 246 between the first pole 230 and the second pole 236, a secondswitch 244 between the second pole 236 and the second throw 234, and athird switch 242 between the first pole 230 and the first throw 232. Tooperate in the various modes, states of the switches 246, 244, 242 canbe selected as listed in Table 1. For the purpose of description, “ON”can refer to a switch being closed and conducting, and “OFF” can referto a switch being open and not conducting.

TABLE 1 Mode First switch 246 Second switch 244 Third switch 242 B28A TxON OFF OFF B28B Tx OFF OFF ON B29 Rx OFF ON OFF

As described herein, the post-PA switch 202 of FIGS. 3 and 4 can includeone additional pole (to yield a DP2T configuration) when compared to thepost-PA switch 146 (a SP2T configuration) of FIG. 2. By providing suchan additional throw at an already existing post-PA switch, the foregoingdual functionality of a filter (e.g., an existing Tx filter such as aB28A Tx filter) can be facilitated. In some implementations, such anadditional throw at the post-PA switch can involve a relatively smallincrease in cost and size. In return, significant cost and/or sizebenefits can be realized by removing a filter (e.g., an Rx filter suchas a B29 Rx filter) and its corresponding throw in an antenna switch.

FIG. 5 shows a process 300 that can be implemented to achieve one ormore features as described herein. In block 302, a wireless network canbe detected. In a decision block 304, the process 300 can determinewhether a change in network is needed based on the detected network. Ifthe answer is Yes, the process 300 in block 306 can induce a changebetween a first signal routing configuration associated with an existingnetwork and a second signal routing configuration associated with a newnetwork. In some embodiments, both of the first and second routingconfigurations can utilize a common filter.

FIG. 6 shows another process 310 that can be implemented to achieve oneor more features as described herein. In block 312, a wireless networkcan be detected. In a decision block 314, the process 310 can determinewhether a change in network is needed based on the detected network. Ifthe answer is Yes, the process 310 in block 316 can induce or perform aswitching operation to change between a Tx signal path associated withone network and an Rx signal path associated with another network. Insome embodiments, both of the Tx and Rx signal paths can utilize acommon filter.

FIGS. 7 and 8 show processes 320 and 340 that can be implemented as morespecific examples of the processes described in reference to FIGS. 5 and6. In the process 320 of FIG. 7, a wireless network can be detected inblock 322. In a decision block 324, the process 320 can determinewhether the detected network is a B28 band. If the answer is Yes, theprocess 320 in block 326 can induce or perform a switching operation todisconnect a B29 Rx path from a B28 Tx filter. In a decision block 328,the process 320 can then determine whether the B28 band is a B28A band.If the answer is Yes, the process 320 in block 330 can induce or performa switching operation to connect a post-PA B28 Tx path with the B28A Txfilter. If the answer is No, the process 320 in block 332 can induce orperform a switching operation to connect a post-PA B28 Tx path with aB28B Tx filter. In some embodiments, the foregoing switch operations canbe performed in sequence determined by the decision blocks, or a set ofswitch status, such as the example of Table 1, can be implementeddirectly after the final mode is determined.

In the process 340 of FIG. 8, a wireless network can be detected inblock 342. In a decision block 344, the process 340 can determinewhether the detected network is a B29 band. If the answer is Yes, theprocess 340 in block 346 can induce or perform a switching operation todisconnect a post-PA B28 Tx path from a B28B Tx filter. In block 348,the process 340 can induce or perform a switching operation todisconnect the post-PA B28 Tx path from a B28A Tx filter. In block 350,the process 340 can induce or perform a switching operation to connect aB29 Rx path with the B28A Tx filter. In some embodiments, such switchoperations associated with blocks 346, 348, 350 can be performedsimultaneously, in sequence, or any combination thereof. In someembodiments, a set of switch status, such as the example of Table 1, canbe implemented directly to effectuate the B29 Rx mode.

In some implementations, an architecture, a device and/or a circuithaving one or more features described herein can be included in an RFdevice such as a wireless device. Such an architecture, a device and/ora circuit can be implemented directly in the wireless device, in one ormore modular forms, or in some combination thereof. In some embodiments,such a wireless device can include, for example, a cellular phone, asmart-phone, a hand-held wireless device with or without phonefunctionality, a wireless tablet, a wireless router, a wireless accesspoint, a wireless base station, etc.

FIG. 9 schematically depicts an example wireless device 400 having oneor more advantageous features described herein. In some embodiments,such advantageous features can be implemented in a duplexer architecture100 as described herein. At least some portion of such a duplexerarchitecture can be implemented in a front-end (FE) module 414.Accordingly, the FE module 414 can include a post-PA switch 208, aduplexer (DPX) assembly 450, and an antenna switch module (ASM) 220,with each component having one or more features described herein. The FEmodule 414 can include a packaging substrate such as a laminatesubstrate configured to receive a plurality of components. Suchcomponents can include some or all of the foregoing post-PA switch 208,duplexer assembly 450, and ASM 220.

PAs in a PA module 412 can receive their respective RF signals from atransceiver 410 that can be configured and operated to generate RFsignals to be amplified and transmitted, and to process receivedsignals. The transceiver 410 is shown to interact with a basebandsub-system 408 that is configured to provide conversion between dataand/or voice signals suitable for a user and RF signals suitable for thetransceiver 410. The transceiver 410 is also shown to be connected to apower management component 406 that is configured to manage power forthe operation of the wireless device 400. Such power management can alsocontrol operations of the baseband sub-system 408 and other componentsof the wireless device 400.

The baseband sub-system 408 is shown to be connected to a user interface402 to facilitate various input and output of voice and/or data providedto and received from the user. The baseband sub-system 408 can also beconnected to a memory 404 that is configured to store data and/orinstructions to facilitate the operation of the wireless device, and/orto provide storage of information for the user.

In the example wireless device 400, outputs of the PAs of the PA module412 are shown to be provided to the FE module 414. Functionalities suchas band-selection can be implemented in the FE module 414. In FIG. 9,received signals are shown to be routed from the FE module 414 to one ormore low-noise amplifiers (LNAs) 418. Amplified signals from the LNAs418 are shown to be routed to the transceiver 410.

Although various examples are described herein in the context of B28 Txand B29 Rx bands, it will be understood that one or more features of thepresent disclosure can be implemented with other cellular frequencybands, including those among the bands listed in Table 2. It will alsobe understood that one or more features of the present disclosure can beimplemented with frequency ranges that do not have designations such asthe examples of Table 2.

TABLE 2 Tx Frequency Rx Frequency Band Mode Range (MHz) Range (MHz) B1FDD 1,920-1,980 2,110-2,170 B2 FDD 1,850-1,910 1,930-1,990 B3 FDD1,710-1,785 1,805-1,880 B4 FDD 1,710-1,755 2,110-2,155 B5 FDD 824-849869-894 B6 FDD 830-840 875-885 B7 FDD 2,500-2,570 2,620-2,690 B8 FDD880-915 925-960 B9 FDD 1,749.9-1,784.9 1,844.9-1,879.9 B10 FDD1,710-1,770 2,110-2,170 B11 FDD 1,427.9-1,447.9 1,475.9-1,495.9 B12 FDD699-716 729-746 B13 FDD 777-787 746-756 B14 FDD 788-798 758-768 B15 FDD1,900-1,920 2,600-2,620 B16 FDD 2,010-2,025 2,585-2,600 B17 FDD 704-716734-746 B18 FDD 815-830 860-875 B19 FDD 830-845 875-890 B20 FDD 832-862791-821 B21 FDD 1,447.9-1,462.9 1,495.9-1,510.9 B22 FDD 3,410-3,4903,510-3,590 B23 FDD 2,000-2,020 2,180-2,200 B24 FDD 1,626.5-1,660.51,525-1,559 B25 FDD 1,850-1,915 1,930-1,995 B26 FDD 814-849 859-894 B27FDD 807-824 852-869 B28 FDD 703-748 758-803 B29 FDD N/A 716-728 B30 FDD2,305-2,315 2,350-2,360 B31 FDD 452.5-457.5 462.5-467.5 B33 TDD1,900-1,920 1,900-1,920 B34 TDD 2,010-2,025 2,010-2,025 B35 TDD1,850-1,910 1,850-1,910 B36 TDD 1,930-1,990 1,930-1,990 B37 TDD1,910-1,930 1,910-1,930 B38 TDD 2,570-2,620 2,570-2,620 B39 TDD1,880-1,920 1,880-1,920 B40 TDD 2,300-2,400 2,300-2,400 B41 TDD2,496-2,690 2,496-2,690 B42 TDD 3,400-3,600 3,400-3,600 B43 TDD3,600-3,800 3,600-3,800 B44 TDD 703-803 703-803

Although various examples are described herein in the context ofcombining functionalities of a Tx path and an Rx path, it will beunderstood that one or more features of the present disclosure can alsobe implemented in other combinations. For example, such combinations caninclude a first Tx path and a second Tx path, as well as a first Rx pathand a second Rx path. Further, although various examples are describedherein in the context of combining functionalities of two paths, it willbe understood that one or more features of the present disclosure canalso be implemented in applications involving more than two paths.

The present disclosure describes various features, no single one ofwhich is solely responsible for the benefits described herein. It willbe understood that various features described herein may be combined,modified, or omitted, as would be apparent to one of ordinary skill.Other combinations and sub-combinations than those specificallydescribed herein will be apparent to one of ordinary skill, and areintended to form a part of this disclosure. Various methods aredescribed herein in connection with various flowchart steps and/orphases. It will be understood that in many cases, certain steps and/orphases may be combined together such that multiple steps and/or phasesshown in the flowcharts can be performed as a single step and/or phase.Also, certain steps and/or phases can be broken into additionalsub-components to be performed separately. In some instances, the orderof the steps and/or phases can be rearranged and certain steps and/orphases may be omitted entirely. Also, the methods described herein areto be understood to be open-ended, such that additional steps and/orphases to those shown and described herein can also be performed.

Some aspects of the systems and methods described herein canadvantageously be implemented using, for example, computer software,hardware, firmware, or any combination of computer software, hardware,and firmware. Computer software can comprise computer executable codestored in a computer readable medium (e.g., non-transitory computerreadable medium) that, when executed, performs the functions describedherein. In some embodiments, computer-executable code is executed by oneor more general purpose computer processors. A skilled artisan willappreciate, in light of this disclosure, that any feature or functionthat can be implemented using software to be executed on a generalpurpose computer can also be implemented using a different combinationof hardware, software, or firmware. For example, such a module can beimplemented completely in hardware using a combination of integratedcircuits. Alternatively or additionally, such a feature or function canbe implemented completely or partially using specialized computersdesigned to perform the particular functions described herein ratherthan by general purpose computers.

Multiple distributed computing devices can be substituted for any onecomputing device described herein. In such distributed embodiments, thefunctions of the one computing device are distributed (e.g., over anetwork) such that some functions are performed on each of thedistributed computing devices.

Some embodiments may be described with reference to equations,algorithms, and/or flowchart illustrations. These methods may beimplemented using computer program instructions executable on one ormore computers. These methods may also be implemented as computerprogram products either separately, or as a component of an apparatus orsystem. In this regard, each equation, algorithm, block, or step of aflowchart, and combinations thereof, may be implemented by hardware,firmware, and/or software including one or more computer programinstructions embodied in computer-readable program code logic. As willbe appreciated, any such computer program instructions may be loadedonto one or more computers, including without limitation a generalpurpose computer or special purpose computer, or other programmableprocessing apparatus to produce a machine, such that the computerprogram instructions which execute on the computer(s) or otherprogrammable processing device(s) implement the functions specified inthe equations, algorithms, and/or flowcharts. It will also be understoodthat each equation, algorithm, and/or block in flowchart illustrations,and combinations thereof, may be implemented by special purposehardware-based computer systems which perform the specified functions orsteps, or combinations of special purpose hardware and computer-readableprogram code logic means.

Furthermore, computer program instructions, such as embodied incomputer-readable program code logic, may also be stored in a computerreadable memory (e.g., a non-transitory computer readable medium) thatcan direct one or more computers or other programmable processingdevices to function in a particular manner, such that the instructionsstored in the computer-readable memory implement the function(s)specified in the block(s) of the flowchart(s). The computer programinstructions may also be loaded onto one or more computers or otherprogrammable computing devices to cause a series of operational steps tobe performed on the one or more computers or other programmablecomputing devices to produce a computer-implemented process such thatthe instructions which execute on the computer or other programmableprocessing apparatus provide steps for implementing the functionsspecified in the equation(s), algorithm(s), and/or block(s) of theflowchart(s).

Some or all of the methods and tasks described herein may be performedand fully automated by a computer system. The computer system may, insome cases, include multiple distinct computers or computing devices(e.g., physical servers, workstations, storage arrays, etc.) thatcommunicate and interoperate over a network to perform the describedfunctions. Each such computing device typically includes a processor (ormultiple processors) that executes program instructions or modulesstored in a memory or other non-transitory computer-readable storagemedium or device. The various functions disclosed herein may be embodiedin such program instructions, although some or all of the disclosedfunctions may alternatively be implemented in application-specificcircuitry (e.g., ASICs or FPGAs) of the computer system. Where thecomputer system includes multiple computing devices, these devices may,but need not, be co-located. The results of the disclosed methods andtasks may be persistently stored by transforming physical storagedevices, such as solid state memory chips and/or magnetic disks, into adifferent state.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Wherethe context permits, words in the above Detailed Description using thesingular or plural number may also include the plural or singular numberrespectively. The word “or” in reference to a list of two or more items,that word covers all of the following interpretations of the word: anyof the items in the list, all of the items in the list, and anycombination of the items in the list. The word “exemplary” is usedexclusively herein to mean “serving as an example, instance, orillustration.” Any implementation described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otherimplementations.

The disclosure is not intended to be limited to the implementationsshown herein. Various modifications to the implementations described inthis disclosure may be readily apparent to those skilled in the art, andthe generic principles defined herein may be applied to otherimplementations without departing from the spirit or scope of thisdisclosure. The teachings of the invention provided herein can beapplied to other methods and systems, and are not limited to the methodsand systems described above, and elements and acts of the variousembodiments described above can be combined to provide furtherembodiments. Accordingly, the novel methods and systems described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the methods andsystems described herein may be made without departing from the spiritof the disclosure. The accompanying claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirit of the disclosure.

What is claimed is:
 1. A front-end system comprising: a first assemblyof filters including a first transmit filter and configured to provide aduplexing functionality in which a first transmit signal is filtered bythe first transmit filter when in a first frequency-division duplexingmode; a second assembly of filters including a second transmit filterand configured to provide a duplexing functionality in which a secondtransmit signal is filtered by the second transmit filter when in asecond frequency-division duplexing mode; a receive path including thefirst transmit filter such that a received signal is filtered by thefirst transmit filter and routed to a receive output node when in thesecond frequency-division duplexing mode; and a switching circuitconfigured to facilitate the routing of the received signal to thereceive output node.
 2. The front-end system of claim 1 wherein each ofthe first assembly of filters and the second assembly of filters furtherincludes a respective receive filter, such that the respective transmitfilter and the respective receive filter are parts of a respectiveduplexer.
 3. The front-end system of claim 1 wherein the receive path isconfigured as a receive-only path.
 4. The front-end system of claim 1wherein the switch circuit is further configured to facilitate switchingbetween the first frequency-division duplexing mode and the secondfrequency-division duplexing mode.
 5. The front-end system of claim 4wherein the receive path is enabled when the front-end system is in thesecond frequency-division duplexing mode.
 6. The front-end system ofclaim 5 wherein the switch circuit includes a double-pole-double-throwswitch functionality to facilitate the switching between the firstfrequency-division duplexing mode and the second frequency-divisionduplexing mode.
 7. The front-end system of claim 6 wherein thedouble-pole-double-throw switch includes a first node coupled to anoutput of a power amplifier, a second node coupled to the receive outputnode of the receive path, a third node coupled to the first transmitfilter, and a fourth node coupled to the second transmit filter.
 8. Thefront-end system of claim 1 further comprising an antenna nodeconfigured to be coupled to an antenna capable of supporting the firstfrequency-division duplexing mode and the second frequency-divisionduplexing mode.
 9. The front-end system of claim 8 further comprising anantenna switch configured to route the first transmit signal to theantenna node when in the first frequency-division duplexing mode, and toroute the second transmit signal to the antenna node when in the secondfrequency-division duplexing mode.
 10. The front-end system of claim 9wherein the antenna switch includes a single-pole-multiple-throwfunctionality, the single pole in communication with the antenna nodeand a throw in communication with each of the first assembly of filtersand the second assembly of filters.
 11. The front-end system of claim 1wherein the front-end system is configured to operate in only one of thefirst frequency-division duplexing mode and the secondfrequency-division duplexing mode at any given time.
 12. The front-endsystem of claim 11 wherein the first frequency-division duplexing modeis configured for operation in a first geographic region and the secondfrequency-division duplexing mode is configured for operation in asecond geographic region.
 13. The front-end system of claim 12 whereinthe first and second geographic regions are sufficiently separated toinhibit operation in one mode in a non-corresponding geographic region.14. The front-end system of claim 1 wherein the front-end system isimplemented in a wireless device.
 15. A method for operating a wirelesssystem, the method comprising: selecting between a firstfrequency-division duplexing mode and a second frequency-divisionduplexing mode; performing a first duplexing operation in which a firsttransmit signal is filtered by a first transmit filter of a firstassembly of filters; and performing a second duplexing operation inwhich a second transmit signal is filtered by a second transmit filterof a second assembly of filters, and in which a received signal isfiltered by the first transmit filter of the first assembly of filtersand routed to a receive output node through a switching circuit.
 16. Themethod of claim 15 further comprising detecting a wireless network andbased on the detected wireless network, selecting between the firstfrequency-division duplexing mode and the second frequency-divisionduplexing mode
 17. A wireless device comprising: a transceiver; afront-end system in communication with the transceiver and including afirst assembly of filters having a first transmit filter and configuredto provide a duplexing functionality in which a first transmit signal isfiltered by the first transmit filter when in a first frequency-divisionduplexing mode, the front-end system further including a second assemblyof filters having a second transmit filter and configured to provide aduplexing functionality in which a second transmit signal is filtered bythe second transmit filter when in a second frequency-division duplexingmode, the front-end system further including a receive path having thefirst transmit filter such that a received signal is filtered by thefirst transmit filter and routed to a receive output node when in thesecond frequency-division duplexing mode, the front-end system furtherincluding a switching circuit configured to facilitate the routing ofthe received signal to the receive output node; and an antenna incommunication with the front-end system, and configured to facilitateeither or both of transmission and reception of signals.
 18. Thewireless device of claim 17 wherein the wireless device is a cellularphone capable of operating in different geographic locations.
 19. Thewireless device of claim 18 wherein the cellular phone is configured tobe capable of operating in the first frequency-division duplexing modeat a first geographic location and in the second frequency-divisionduplexing mode at a second geographic location, the first and secondgeographic locations sufficiently separated to inhibit operation in onemode in a non-corresponding geographic region.
 20. The wireless deviceof claim 17 wherein the antenna is configured to facilitate transmissionof the first transmit signal when in the first frequency-divisionduplexing mode, transmission of the second transmit signal when in thesecond frequency-division duplexing mode, and reception of the receivedsignal when in the second frequency-division duplexing mode.